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Would TB Out of Adjustment Cause "Buzziness?" 2009 R1200RT

I just had the 6K mile service performed on my 2009 R1200RT at the local dealer. I watched the valve adjustment, but I didn't see the tech adjust the throttle bodies like he used to do on my '04 RT. I asked him about it and he said the computer performs the TB adjustments on the hexheads. I was suspicious of that, but he knows more than I do. I went out to Big Bend last weekend and traveled mostly 75 to 85 mph (4000-4500 rpm in 6th gear). The "buzziness" was uncomfortable over a period of time -- I need to do something before my next trip. Can TBs out of adjustment cause "buzziness" when the engine is pulling at higher rpms? I can let off throttle and pull in clutch (and coast) and the buzziness subsides when there is no stress on engine. Also, while traveling high speed downhill the buzziness subsides. So, I don't think the problem is tire balance or wheel alignment. I hate to even ask, but could problem be in the drive train somewhere? (Bike has only 8,400 miles on it.) Would very much appreciate the collective wisdom of this forum to help me problem-solve this. TIA

Yes, TB's out of adjustment will cause a buzz at high RPM that you will feel in the grips. Mine were slightly out of adjustment and I had Steve (Henzilla) fix the problem. Anything above 80MPH now is smooth.

There is no idle balance adjustment other than by doing a good job when adjusting your valves. Off idle can be adjusted. Check for slack in the cables then adjust cable on one side for balance at 1400~1800 RPM (just off idle) with the engine at full operating temperature.

What they all said. The computer and idle steppers set idle synch, but synchronizing the cables for operation off idle is still necessary. And bad synchronization is probably the number one cause of buzziness.

Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russellhttp://web.bigbend.net/~glaves/

I'd find a new mechanic. If he stated what you said, I'd question how well he did the valve adjustment.

My experience has been (on multiple R1200xx's) - if the valve adjustment is done correctly, the TB balance really doesn't have to be touched. If it wasn't done correctly, people tend to "compensate" with the TB balance, which really doesn't fix much (it may help at some distinct RPM range, but buzz will be there at other RPM ranges.) Once the valves are correct, I check the balance and typically don't have to lay a wrench to the TBs. I think BMW got the cable routing/lengths right on the R12 bikes, they just don't drift out of balance like the R11 bikes do (and even worse - airheads.)

BTW - please read: http://forums.bmwmoa.org/showthread.php?t=46055 - I've added this to your thread title. Given your model, I suspect the reason the mechanic didn't do a TB sync is that plastic has to be removed to access the adjusters. I believe you can do the valve adjustment with the plastic on.. but the plastic pretty much hides the throttle bodies on the RTs.

Agreed;

Don's right on. I think the new bikes are much better than previous TB model beemers of old. I have heard too, dozens of stories of bikes coming out of BMW shops, running worse than before going in. I think the TB experience is one even the best wrenches, or others struggle with, computer or not! Seen it too many times. MY current GSA1200, its a rare day when the TBs are needing any looksee, BUT. I also carry my trusty TwinMax adjuster, everywhere I go(saddlebag) and I guess its from the older days when you really needed one. I still like the ability to see my adjust on the TBs, if need be and its a cool tool. Its a very easy, less than 5 minute test, anywhere I am on my GSA. Your RT, maybe a little longer. Adjusting? A tad longer if its a needed phenom. ONE ADDED NOTE; The pullies the cables go through on the TBs are, or used to be exposed to open air and just on rare occasions could attract debris and would definately cause an issue, out of synch'ness immediately. A GS phenom, with all the offroading, a more likely event. Hard to see up in there! I have personally seen a tiny pebble get stuck in mine and it took me days to find it, much hassle. Randy

2009 RT "Buzziness"

Thanks for the advice and recommendations on my RT "buzziness." My riding buddy and I re-adjusted the valves and TBs this morning. Both valves and TBs were quite a bit off optimum settings. I took it out for a test ride and the engine is noticably smoother at higher rpm. So now I'm wondering if there is anything more I can do to further reduce vibration at high speeds. I read a post by a knowledgable BMWST Forum member about "buzziness" increasing in hexheads & camheads as compared to older oilheads. One of the remedies he tried on his hexhead was "changing the tuning mass on the outer bar ends." I'm not sure what this entails -- increasing the weight of the bar ends? I know there are some aftermarket bar ends that are slightly heavier than the stock bar ends. Does anyone have any experience with and would recommend aftermarket bar ends as an additional dampening device?

With all the above said.....

When riding with my wife last summer on my '06 R1200RT in Glacier National Park of course there was construction and stop and go traffic, uphill. We all know what a fast first gear we have, and a lot of times the motors don't idle all that smooth on the idle stop. They run much smoother when the TBs are hanging off of the cable. Stay with me I will get to my point. When you add a little throttle now you are going to fast. My question is does anybody balance the idle with one of the locktited screws for the idle stop? I know people say you shouldn't but............ My TBs are synced.

My question is does anybody balance the idle with one of the locktited screws for the idle stop? I know people say you shouldn't but............ My TBs are synced.

That's a very BAD idea. These are not idle stops.. they are TB stops which leave the butterfly valves just completely closed. If you adjust them one is likely to stick when it tries to close further. These are set at the factory and are intended to never ever be adjusted.

Thanks for the advice and recommendations on my RT "buzziness." My riding buddy and I re-adjusted the valves and TBs this morning. Both valves and TBs were quite a bit off optimum settings. I took it out for a test ride and the engine is noticably smoother at higher rpm. So now I'm wondering if there is anything more I can do to further reduce vibration at high speeds. I read a post by a knowledgable BMWST Forum member about "buzziness" increasing in hexheads & camheads as compared to older oilheads. One of the remedies he tried on his hexhead was "changing the tuning mass on the outer bar ends." I'm not sure what this entails -- increasing the weight of the bar ends? I know there are some aftermarket bar ends that are slightly heavier than the stock bar ends. Does anyone have any experience with and would recommend aftermarket bar ends as an additional dampening device?

My experience has been the exact opposite of your friends. BMW added a balance shaft to the hexhead (and camhead) engine to reduce vibration at medium engine speeds. It has the effect of very slightly increasing the vibration at max RPMs.

There are heavy bar-ends available. Adding mass to the ends of the bar will lower the resonant frequency, so if the bar is resonating with the vibrational frequency this will help. They aren't terribly costly.

FWIW - I couldn't stand the vibes/buzz on my '04 R1150RS.. it drove me to the R12R (thank Dog!)

Valves need to be set to as close as an exact match as possible to minimize vibes. Unless you're blessed with really good feel for using a pair of identical feelers, you'll proably get closest with a go/ no-go set of gauges which allow most anyone to get to closest .001".
Re throttle body synch- you can get a crude idea by vacuum checks which is what some do to avoid pulling plastic. But only ways to do it right and using one of the usual tools (a manometer set, Twin Max, Harmonizer, etc) and adjusting the throttle side cable (only). If it doesn't hold a close synch across the complete rpm band after being set spot on at 1400-1800, there is something wrong that needs to be corrected.
Idle stepper motots on hexheads on newer don't have much to be with vibes at speed- they just control idle.

Bar weights help as good grip puppies or beemer buddies (foam grips). I added weight by adding S-7 Barkbusters...

I almost hate to mention this, but another contributor to vibration is if the oil is overfilled. Since you stated the problem started after you had the bike serviced, it is worth checking especially since your original mechanic seems marginally capable.